Paddled that boat for years, good creeker! the cap is like the bumper on a car, it'll deflect cats and small children but a moose will still mess you up. Old Pyranha plastic was great, I buckled my boat during a pin in CA and stomped it back into shape, no oil can or nothing.
Because it's an older boat the plastic might still be fragile, regardless of usage. Just make sure the price is right (I sold mine for $200, 4 years ago)
"Paddle silently, boof loudly"